Anteroposterior Pelvis Research Articles

Outcome of Neonatal Hydronephrosis, a New Cut-Off to Identify Patients with Spontaneous Resolution

Background/Objectives: The anteroposterior renal pelvis diameter (APRPD) is used to assess the grade of urinary tract dilatation (UTD). There is no univocal method stratifying the risk of complications related to postnatal UTD. This study aims to identify APRPD cut-offs at birth to determine outcome stratification and second-level exams. Methods: The records of a cohort of newborns with unilateral or bilateral UTD confirmed or detected by ultrasound after birth between 2010 and 2020 were analyzed. These children underwent further examinations at 3, 6, 12, and 24 months of age. Results: We managed 500 children with postnatal UTD, with a median APRPD at 0–2 months of age of 7.7 mm [IQR 6.0–10.0]. As for UTD resolution, 279 (55.8%) patients had a complete resolution at the age of 6 months; an additional 55, for a total of 344 (68.8%), at 9–12 months; and 19, for a total of 353 (70.6%), at 24 months. An APRPD value ≤ 8.5 mm showed a sensitivity of 80.4% (95% CI [76.0–84.4]) and a specificity of 100.0% (95% CI [76.8–100.0]) in identifying candidates for spontaneous resolution within 24 months of life. An APRPD value ≤ 8.5 mm was also an independent prognostic factor of resolution at the age of 24 months (p = 0.000). Conclusions: Isolated hydronephrosis is the most frequent urinary tract abnormality detected in pregnancy. A well-structured prenatal and postnatal management plan is indeed necessary. According to our analyses, 8.5 mm can be used as a cut-off to reassure parents and clinicians of the benignity of the postnatal dilatation.

Relationship Between Hip and Groin Pain and Hip Range of Motion in Amateur Soccer and Australian Rules Football Players

Background: The relationship between hip/groin pain and hip range of motion (ROM) is unclear. Purpose: To explore the relationship between hip/groin pain and hip joint ROM and examine the influence of sex and cam morphology on this relationship. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Included were 184 amateur soccer and Australian Rules football players (276 hips; 20% women; median age, 26 years; interquartile range, 24-30 years) with hip/groin pain >6 months and a positive flexion-adduction-internal-rotation (FADIR) test, and 50 matched asymptomatic control players (98 hips; 28% women, median age, 26 years; interquartile range, 23-31 years). Hip ROM measures were flexion, internal and external rotation at 90° of hip flexion, total rotation (internal and external), and bent-knee fall out (BKFO). Cam morphology was determined from anteroposterior pelvis or 45° Dunn radiographs, defined by an alpha angle ≥60°. Linear regression models with generalized estimating equations were used to examine the relationship between group (symptomatic and asymptomatic) and each ROM measure. Interaction terms (group × cam morphology or group × sex) were included to examine if relationships between group and hip ROM were influenced by cam morphology or sex. Where appropriate, models were adjusted for sex, age, and cam morphology. Results: An interaction between the relationship between group × cam and internal rotation ROM was found. Symptomatic players with cam morphology had lower internal rotation ROM than controls with cam morphology (adjusted mean difference [AMD] = −4.5°; 95% CI, −7.4° to −1.6°). Hip/groin pain was not associated with internal rotation ROM if cam morphology was absent. A significant interaction was also found for group × sex and BKFO and total rotation ROM. Symptomatic women had lower total rotation ROM than control women (AMD = −8.2°; 95% CI, −14.1° to −2.2°), but no difference was seen in men. BKFO range was lower in men with hip/groin pain compared with control men (AMD = 1.6 cm; 95% CI, 0.3-3.0 cm), but no difference was seen in women. Flexion and external rotation ROM did not differ between symptomatic and control hips. Conclusion: Cam morphology was an effect modifier of the relationship between hip/groin pain and internal rotation ROM. Sex-related differences were also observed in the relationship between hip/groin pain and hip ROM.

The Measurement of the Lateral Center-Edge Angle Is Underestimated on Radiographs Compared With 3-Dimensional Computed Tomography

PurposeTo determine if there is a significant difference using Femoral Heads (FH) as anatomical horizon when measuring the LCEA compared to Floor (F), Acetabular Teardrops (AT), and Ischial Tuberosities (IT) and to determine their accuracy by comparing to CT scan with commercially available software. MethodsBetween June 2019 and May 2020, patients with preoperative supine anteroposterior (AP) pelvis radiographs and CT scans were included and retrospectively analyzed. The LCEA was measured on all preoperative supine AP pelvis radiographs four times per hip, using the four methods. The four anatomical horizons used to measure LCEA were compared to each other to determine statistically significant difference. The LCEA measured in the CT scan at the 12 o’clock position was used to compare and determine radiographs’ LCEA accuracy. ResultsNinety-six patients (100 hips) met the inclusion criteria. Sixty-two were females (65%), and the mean age was 35.2 ± 15 years. The mean value for LCEA in CT was 32.2 and 31.1 for the four anatomical horizons in X-ray (P < 0.001). The lowest mean difference between CT scan and X-ray was obtained using the FH (2.3 ± 2.4). Less mean difference was obtained between FH and IT (1.0 ± 0.8). ConclusionIn this study, radiographic measurements underestimated LCEA compared with those from CT scans. Using the FH as an anatomic horizon on radiographs was a more accurate method to measure LCEA than using AT, IT, or F. While this difference is statistically significant, it is not likely to be clinically significant.

Is it feasible to develop a supervised learning algorithm incorporating spinopelvic mobility to predict impingement in patients undergoing total hip arthroplasty?

Precise implant positioning, tailored to individual spinopelvic biomechanics and phenotype, is paramount for stability in total hip arthroplasty (THA). Despite a few studies on instability prediction, there is a notable gap in research utilizing artificial intelligence (AI). The objective of our pilot study was to evaluate the feasibility of developing an AI algorithm tailored to individual spinopelvic mechanics and patient phenotype for predicting impingement. This international, multicentre prospective cohort study across two centres encompassed 157 adults undergoing primary robotic arm-assisted THA. Impingement during specific flexion and extension stances was identified using the virtual range of motion (ROM) tool of the robotic software. The primary AI model, the Light Gradient-Boosting Machine (LGBM), used tabular data to predict impingement presence, direction (flexion or extension), and type. A secondary model integrating tabular data with plain anteroposterior pelvis radiographs was evaluated to assess for any potential enhancement in prediction accuracy. We identified nine predictors from an analysis of baseline spinopelvic characteristics and surgical planning parameters. Using fivefold cross-validation, the LGBM achieved 70.2% impingement prediction accuracy. With impingement data, the LGBM estimated direction with 85% accuracy, while the support vector machine (SVM) determined impingement type with 72.9% accuracy. After integrating imaging data with a multilayer perceptron (tabular) and a convolutional neural network (radiograph), the LGBM's prediction was 68.1%. Both combined and LGBM-only had similar impingement direction prediction rates (around 84.5%). This study is a pioneering effort in leveraging AI for impingement prediction in THA, utilizing a comprehensive, real-world clinical dataset. Our machine-learning algorithm demonstrated promising accuracy in predicting impingement, its type, and direction. While the addition of imaging data to our deep-learning algorithm did not boost accuracy, the potential for refined annotations, such as landmark markings, offers avenues for future enhancement. Prior to clinical integration, external validation and larger-scale testing of this algorithm are essential.

The Association Between the Development of Cam Morphology During Skeletal Growth in High-Impact Athletes and the Presence of Cartilage Loss and Labral Damage in Adulthood: A Prospective Cohort Study With a 12-Year Follow-up

Background: Cam morphology develops during skeletal growth, but its influence on cartilage and the labrum in high-impact athletes later in life is unknown. Purpose: To (1) explore the association between the presence and duration of cam morphology during adolescence and the cartilage and labral status 7 to 12 years later and (2) report the prevalence of cartilage loss and labral damage in a population of young male athletes (<32 years old) who played professional soccer during skeletal growth. Study Design: Cohort study (Prognosis); Level of evidence, 2. Methods: A total of 89 healthy male academy soccer players from the Dutch soccer club Feyenoord (aged 12-19 years) were included at baseline. At baseline and 2.5- and 5-year follow-ups, standardized supine anteroposterior pelvis and frog-leg lateral radiographs of each hip were obtained. At 12-year follow-up, magnetic resonance imaging of both hips was performed. Cam morphology was defined by a validated alpha angle ≥60° on radiographs at baseline or 2.5- or 5-year follow-up when the growth plates were closed. Hips with the presence of cam morphology at baseline or at 2.5-year follow-up were classified as having a “longer duration” of cam morphology. Hips with cam morphology only present since 5-year follow-up were classified as having a “shorter duration” of cam morphology. At 12-year follow-up, cartilage loss and labral abnormalities were assessed semiquantitatively. Associations were estimated using logistic regression, adjusted for age and body mass index. Results: Overall, 35 patients (70 hips) with a mean age of 28.0 ± 2.0 years and mean body mass index of 24.1 ± 1.8 participated at 12-year follow-up. Cam morphology was present in 56 of 70 hips (80%). The prevalence of cartilage loss was 52% in hips with cam morphology and 21% in hips without cam morphology (adjusted odds ratio, 4.52 [95% CI, 1.16-17.61]; P = .03). A labral abnormality was present in 77% of hips with cam morphology and in 64% of hips without cam morphology (adjusted odds ratio, 1.99 [95% CI, 0.59-6.73]; P = .27). The duration of cam morphology did not influence these associations. Conclusion: The development of cam morphology during skeletal growth was associated with future magnetic resonance imaging findings consistent with cartilage loss in young adults but not with labral abnormalities.

Paper 17: Does Higher Quality CAM Resection Correlate with Better Patient-Reported Outcomes?

Objectives: The relationships between CAM resection quality and patient-reported outcomes (PROs) are unknown in the literature. This study aimed to investigate the correlation of CAM resection quality with patient’s self-reported International Hip Outcome Tool (iHOT) scores collected annually post-surgery. Methods: A retrospective analysis was conducted including patients who underwent primary hip arthroscopy for femoroacetabular impingement (FAI) between 2012 and 2019. Inclusion criteria were pre-operative radiographic signs of CAM-type impingement (alpha angle &gt; 55 °) and post-operative plain radiographs. Exclusion criteria were radiographic signs of a pincer or mixed impingement, history of femoral neck or proximal femur fracture, and treatment of concomitant hip pathologies. The following data were collected: demographic information, radiographic findings, and iHOT scores. CAM resection quality data were categorized based on findings from three plain radiographs (anteroposterior (AP) pelvis, frog leg lateral, and 45° Dunn views). High quality resections were defined as those post-operative alpha angle &lt;55°. Results: This study included 148 participants who underwent CAM resection. From Frog leg views, 88% of patients had high-quality resections and presented superior post-operative iHOT scores compared to the 12% of patients with poor resection quality during the 1-year to 5-year follow-up period. Likewise, from Dunn views 82% of patients with a high-quality CAM resection displayed a similar trend in post-operative iHOT scores compared to 18% of patients with poor resection quality on Dunn views. However, this positive association between resection quality and post-operative iHOT scores was not evident in AP imaging. With AP views, 82% of patients with high-quality resections did not show a significant difference in iHOT scores compared to 18% of patients with poor resection quality. Conclusions: This study found that high quality CAM resection from arthroscopic surgery correlated with better iHOTs up to 5-years post-surgery from the Dunn and frog leg radiographic imaging views.

Risk Factors for Trochanteric Bursitis Following Total Hip Arthroplasty: A Radiographic Analysis

BackgroundTrochanteric bursitis (TB) is a prevalent complication following total hip arthroplasty (THA), with increased offset hypothesized as a potential risk factor. This study investigated potential TB predictors in THA patients, including radiographic measurements of offset and leg length, comorbidities, and patient characteristics. MethodsIn this retrospective cohort study, all THA patients from a single academic tertiary care center between 2005 and 2021 were reviewed. Exclusion criteria included less than one-year follow-up, osteonecrosis, or fracture. Manual radiographic measurements of offset (acetabular, femoral, and total) and leg length from preoperative and postoperative antero-posterior pelvis X-rays were taken, with scaling using femoral cortical diameter. Univariable and multivariable Cox proportional hazard models were employed to estimate TB risk. ResultsOf 1,094 patients, 103 (9.4%) developed TB, with a median (Q1, Q3) time to presentation of 41.8 weeks (25.5, 66.9). In univariable models, only sex was associated with increased TB risk, with women exhibiting a 1.79 times increased risk (hazard ratio: 1.79 (1.16, 2.76), P = .009). Changes in acetabular offset, femoral offset, total offset, and leg length between preoperative and postoperative radiographs were not associated with an increased risk of developing TB in the univariate or multivariate models. Furthermore, various offset thresholds were evaluated, with no amount of increased offset showing increased TB risk. ConclusionsThis study found no relationship between femoral, acetabular, or total offset and TB following THA. These findings suggest that surgeons may consider adding offset for increased prosthetic stability in high-risk cases. However, given that this is a retrospective study, the authors are not advocating for the routine use of increased offset. The study identified women as a risk factor with a 1.79 times higher TB risk, highlighting the importance of counseling women patients on this heightened risk.

Decreasing Hip Offset in Total Hip Arthroplasty Results in Decreased Physical Function Scores

BackgroundAcetabular and femoral offset play an important role in total hip arthroplasty (THA) for postoperative stability and biomechanical function. However, it is unknown whether offset impacts patient-reported outcomes (PROs). This study evaluated patients undergoing direct anterior (DA) THA with the hypothesis that patients who have a decrease in hip offset postoperatively would have lower physical function scores and higher pain interference. MethodsThere were 499 patients who underwent DA THA at a single tertiary academic institution who were retrospectively evaluated. Preoperative and postoperative hip offset was measured by 2 reviewers using the Sundsvall method on standing anteroposterior pelvis radiographs. Postoperative changes in hip offset were categorized as increased (> 5 mm), matched (within 5 mm of the preoperative offset measurement), or decreased ( >5 mm). Postoperative PROs with a minimum 1-year follow-up were recorded. A one-way analysis of variance was utilized to compare postoperative pain and PROs between groups. ResultsPatients who had decreased offset had the lowest mean postoperative physical function scores at 39.4 (8.0), followed by the increased offset group at 42.2 (10.4) and the matched offset group at 42.8 (9.8) (P < .01). There were significant differences in postoperative physical function scores between matched offset (42.8) and decreased offset (39.4) groups (P < .01), as well as between increased offset (42.2) and decreased offset (39.4) groups (P = .04). There was no difference between matched and increased offset cohorts. ConclusionsOur data suggests that reducing hip offset may result in worse physical function scores compared to those who have matched or increased hip offset. This should be considered intraoperatively, and efforts should be made to avoid reduced offset even in the presence of hip stability.

Ultrasound evaluation of stiffness and vascularity of renal parenchymal damage secondary to hydronephrosis in pediatric patients using shear wave elastography and superb microvascular imaging

AbstractAimsThe purpose of this study is to assess the diagnostic value of SWE (shear wave elastography) and renal parenchymal elasticity and microvascularization with the SMI (super microvascular imaging) technique in diagnosing and predicting the progression of renal parenchymal damage in pediatric patients with hydronephrosis.Patients and MethodsA total of 45 patients were included in the prospective study. To evaluate parenchymal changes, SWE and SMI‐Vacularity Index (VI) measurements were performed in various sections of the affected and normal kidneys. The affected and control renal pelvises' anteroposterior (AP) diameters were also measured.ResultsThe average SWE values were measured as 16.62 kPa for the affected kidneys, whereas the control kidneys showed an average SWE value of 12.70 kPa, indicating a statistically significant difference (p &lt; .01). Furthermore, in the affected kidneys, the average SMI‐VI value was measured as 5.92, whereas the control kidneys exhibited a higher average SMI‐VI value of 6.64, showing a statistically significant difference (p &lt; .01). A reverse correlation was found between renal pelvis AP diameter and SMI‐VI values, while a positive correlation existed between renal pelvis AP diameter and SWE values.ConclusionsWe believe that SWE and SMI may be useful for diagnosing and predicting the progression of renal parenchymal damage in pediatric hydronephrotic patients.

Should a Refluxing Internal Diversion Be Considered a Temporizing Procedure? Extended Follow-Up and Outcomes After Side-to-Side Ureterovesicostomy for Primary Obstructive Megaureter in Young Children.

We describe long-term outcomes, including UTIs and need for reimplantation, after ureterovesicostomy (UV) as a lasting surgical procedure for children with primary obstructive megaureter (POM). Children referred to our institution between 2016 and 2023 who underwent refluxing UV were analyzed. POM was defined as hydroureteronephrosis with distal ureteral dilatation > 7 mm and a negative workup for other etiologies of hydronephrosis. We assessed for surgical outcomes, complications, rate of UTI, and improvement in upper tract dilatation. Statistical analyses assessed for change in hydronephrosis metrics over follow-up. Among 183 patients diagnosed with POM, 47 (24%) underwent UV. Median age of presentation, surgery, and follow-up was 2, 9, and 43 months, respectively. A total of 7 patients developed 30-day complications: Clavien-Dindo grade 1 in 2 (transient urinary retention) and grade 2 in 5 (UTIs). During monitoring 14 (30%) developed UTIs and 7 (15%) required ureteral reimplant or UV takedown. After surgery there was a significant decrease in the proportion of patients with high-grade hydronephrosis, anteroposterior renal pelvis diameter, and maximum ureteral dilatation. Refluxing UV is a safe alternative to cutaneous diversion in POM. Most patients had improvement in upper tract dilatation with an acceptable short-term complication rate and need for reoperation (in comparison to routine later reimplantation). Our experience suggests that monitoring alone after UV is feasible, and that selective subsequent reconstruction is a reasonable strategy.

Comparison of robot-assisted single-port-plus-one pyeloplasty vs. laparoscopic single-port pyeloplasty in the treatment of ureteropelvic junction obstruction in children.

To compare the efficacy of robot-assisted single-port-plus-one pyeloplasty (RSPY) and laparoscopic single-port pyeloplasty (LSPY) in the treatment of children with ureteropelvic junction obstruction (UPJO). The clinical data of 47 children who underwent surgery for UPJO at the Department of the Pediatric Surgery of the Fujian Provincial Hospital from October 2020 to September 2022 were analyzed retrospectively. Of these 47 children, 27 received RSPY while 20 underwent LSPY. The baseline data, operation time, intraoperative anastomosis time, intraoperative blood loss, postoperative hospital stay, complications, total cost, preoperative and postoperative renal parenchymal thickness (PT), anteroposterior renal pelvis diameter (APD), and differential renal function (DRF) of the two groups were compared to evaluate the clinical efficacy of the two surgical methods. The results showed that both surgical techniques were successful and no patient transitioned to open surgery. There was no significant difference between the two groups in baseline data, intraoperative blood loss, complications, APD, and PT 6 months after surgery. There was also no significant difference in APD, PT, and DRF 12 months after surgery (all P > 0.05). Compared with the LSPY group, the RSPY group had shorter operation time [(153.04 ± 14.44) vs. (189.90 ± 32.59) min, t = -5.24, P < 0.05], less intraoperative anastomosis time [(68.81 ± 16.80) vs. (97.45 ± 11.99) min, t = -6.49, P < 0.05], shorter postoperative hospital stay [(5.96 ± 1.34) vs. (9.00 ± 1.33) d, t = -7.68, P < 0.05], but higher total cost [(57,390 ± 7,664) vs. (30,183 ± 4,219) yuan, t = 14.32, P < 0.05]. Compared with LSPY, RSPY achieves equivalent efficacy in the treatment of UPJO in children and has certain advantages by shortening the operation time, intraoperative anastomosis time, and postoperative hospital stay. However, its cost burden is heavy, and appropriate cases need to be selected for popularization and application.

Three Differing Methods of Treating Intraoperative Nondisplaced Calcar Fractures Demonstrate Similar Radiographic Stem Subsidence

BackgroundSeveral management strategies have been described to treat intraoperative calcar fractures during total hip arthroplasty (THA), including retaining the primary implant and utilizing cerclage cables (CCs) or switching the implant to one that bypasses the fracture and achieves diaphyseal fixation. However, the radiographic and clinical outcomes of these differing strategies have never been described and compared. MethodsWe retrospectively identified 50 patients who sustained an intraoperative calcar fracture out of 9,129 primary total hip arthroplasties (0.55%) performed by one of three surgeons between 2008 and 2022. Each of the three surgeons consistently employed a distinct strategy for the management of these fractures: retention of the primary metaphyseal-engaging implant and placement of CCs; exchange to a modular, tapered-fluted stem (MTF); or exchange to a fully-coated, diaphyseal-engaging stem (FC). Stem subsidence was then evaluated on standing anteroposterior pelvis radiographs at three months and one year postoperatively. Postoperative medical and surgical complication rates were evaluated. ResultsA total of fifteen patients were treated with CC, 15 with MTF, and 20 with FC. At three-month follow-up, mean stem subsidence was 0.43 ± 0.08 mm, 1.47 ± 0.36 mm, and 0.68 ± 0.39 mm for CC, MTF, and FC cohorts, respectively (P = .323). At one-year, mean stem subsidence was 0.70 ± 0.08 mm, 1.74 ± 0.69 mm, and 1.88 ± 0.90 mm for the CC, MTF, and FC cohorts, respectively (P = .485). Medical complications included 2 venous thromboembolic events (4%) within 90 days of surgery. There were 6 reoperations (12%); 3 (6%) for acute periprosthetic joint infection (all within the FC cohort); 2 (4%) for postoperative periprosthetic fractures (one fracture distal to the stem in the FC cohort and one fracture at the level of the stem in the MTF cohort), and 1 (2%) closed reduction for instability (within the CC cohort). ConclusionsThe three described methods of managing intraoperative nondisplaced calcar fractures demonstrated little radiographic stem subsidence; however, the risk of reoperation was much higher than expected.

Comparison of artificial intelligence algorithm for the diagnosis of hip fracture on plain radiography with decision-making physicians: a validation study.

This study aimed to compare an algorithm developed for diagnosing hip fractures on plain radiographs with the physicians involved in diagnosing hip fractures. Radiographs labeled as fractured (n=182) and non-fractured (n=542) by an expert on proximal femur fractures were included in the study. General practitioners in the emergency department (n=3), emergency medicine (n=3), radiologists (n=3), orthopedic residents (n=3), and orthopedic surgeons (n=3) were included in the study as the labelers, who labeled the presence of fractures on the right and left sides of the proximal femoral region on each anteroposterior (AP) plain pelvis radiograph as fractured or non-fractured. In addition, all the radiographs were evaluated using an artificial intelligence (AI) algorithm consisting of 3 AI models and a majority voting technique. Each AI model evaluated each graph separately, and majority voting determined the final decision as the majority of the outputs of the 3 AI models. The results of the AI algorithm and labelling physicians included in the study were compared with the reference evaluation. Based on F-1 scores, here are the average scores of the group: majority voting (0.942) > orthopedic surgeon (0.938) > AI models (0.917) > orthopedic resident (0.858) > emergency medicine (0.758) > general practitioner (0.689) > radiologist (0.677). The AI algorithm developed in our previous study may help recognize fractures in AP pelvis in plain radiography in the emergency department for non-orthopedist physicians. Level IV, Diagnostic Study.

The Empty Ischial Fossa Sign: A Visual Representation of Relative Inadequate Anteversion in the Posteriorly Tilted Pelvis

BackgroundInstability is a known complication following total hip arthroplasty (THA) and is influenced by spinopelvic alignment. Radiographic markers have been investigated to optimize the acetabular cup position. This study evaluated if the empty ischial fossa (EIF) sign and the position of the trans-teardrop line were predictive of postoperative instability. MethodsAll patients who underwent THA from 2011 to 2018 at a single institution were retrospectively reviewed. Pelvic tilt was measured using a trans-teardrop line compared to the superior aspect of the pubic symphysis on standing anteroposterior pelvis radiographs. Postoperative dislocations were identified through chart review and radiographic review. The EIF sign was determined by the presence of uncovered bone below the posterior inferior edge of the acetabular component at the level of the native ischium and posterior wall on standing postoperative anteroposterior radiographs. ResultsOne thousand seven hundred fifty patients (952 anterior approach and 798 posterior approach) were included. The EIF sign was present in 458 patients (26.2%) and associated with an increased dislocation rate (3.9% vs 0.9%, P < .0001). Patients with spondylosis/instrumented fusion, and positive EIF sign had a dislocation risk of 5.1% vs 1.3% (P = .001). A postoperative outlet pelvis was not significant for increased dislocation risk (odds ratio 2.16, P = .058). Patients with combined spondylosis/fusion, posterior approach, outlet pelvis, and EIF sign had a dislocation rate of 14.5%. ConclusionsThe EIF sign was an independent risk factor for postoperative instability and may represent failure to account for pelvic tilt. Avoidance of the EIF sign during cup positioning may help reduce dislocations following THA.

Liaw's Ellipse Anteversion Method for Distinguishing Acetabular Component Retroversion from Anteversion on Plain Radiographs.

Improper acetabulum component position is a significant risk factor for postoperative dislocation after total hip arthroplasty. Several radiographic two-dimensional methods exist for measuring acetabulum component anteversion, but they cannot distinguish between anteversion and retroversion. "Liaw's version," initially proposed as a simple mathematical standardized two-dimensional method, was modified to the computerized ellipse method, proving superior accuracy to traditional two-dimensional methods. In this article, we demonstrated its application in detecting and measuring retroverted acetabulum component. We obtained anteroposterior pelvis radiographs from a patient undergoing total hip arthroplasty on the day of surgery and 2 weeks postoperatively. The computerized ellipse method was used to measure the acetabulum component orientation. Upon comparison, the difference between θ assigned to be retroverted (9.52-8.56 = 0.96) is much smaller than the difference between θ assigned to be anteverted (23.81-18.86 = 4.95), leading us to determine retroversion. This was further confirmed by computed tomography at the 6-week follow-up. We propose that using the computerized ellipse method to measure Liaw's version can be a valuable tool in identifying acetabulum component retroversion on anteroposterior radiographs during routine postoperative follow-up and retrospective assessments of total hip arthroplasty patients.

Evaluating Pelvic Tilt Using the Pelvic Antero-Posterior Projection Images: A Systematic Review

BackgroundPelvic tilt (PT) is a routinely evaluated parameter in hip and spine surgeries, and is usually measured on a sagittal pelvic radiograph. This may not always be feasible due to limitations such as landmark visibility, pelvic anomaly, and hardware presence. Tremendous efforts have been dedicated to using pelvic antero-posterior (AP) radiographs for assessing sagittal PT. Thus, this systematic review aimed to collect these methods and evaluate their performances. MethodsTwo independent reviewers searched the PubMed, Ovid, Cochrane, and Web of Science databases in June 2023 with backward reference trailing (Google Scholar archive). There were 30 studies recruited. Risk of bias was assessed using the prediction model risk of bias assessment tool. The relevant data were tabulated in a standardized form for evaluating either the absolute PT or relative PT. Disagreement was resolved by discussing with the senior author. ResultsThere were 19 parameters from pelvic AP projection images involved, with 4 studies which used artificial intelligence, eyeball, or statistical shape method not involving a specific parameter. In comparing the PT values from pelvic sagittal images with those extrapolated from antero-posterior projection images, the highest correlation coefficient was found to be 0.91. The mean absolute difference (error) was 2.6°, with a maximum error reaching 10.9°. Most studies supported the feasibility of using AP parameters to calculate changes in PT. ConclusionsNo individual AP parameter was found to precisely estimate absolute PT. However, relative PT can be derived by evaluating serial AP radiographs of a patient in varying postures, employing any AP parameters.

Pelvis radiographs in children with cerebral palsy: effects of patient positioning on calculating migration percentages.

Hip displacement in children with cerebral palsy (CP) is monitored by measuring migration percentage on anteroposterior pelvis radiographs. However, proper positioning for radiography in children with spasticity is difficult. The reliability and accuracy of migration percentage as a function of patient positioning is unknown. To determine the effects of patient positioning on migration percentage measurements in children with CP. We identified children with CP (≤18-year-old) with pelvis CT and anteroposterior pelvis radiograph obtained <6 months apart (10/2018-11/2021). Digitally reconstructed radiographs were generated from each pelvis CT, to simulate nine different patient positions: neutral; 10° and 20° lordosis and kyphosis; and 10° and 20° right rotation and left rotation. Two radiologists measured migration percentages from the simulated and real pelvis radiographs. We used Spearman's rho to assess inter-rater reliability, and Wilcoxon signed rank test to determine statistical significance. We studied sixty-three children (male=41; median age=8 years; range=4-18 years). The two radiologists' migration percentage measurements were highly correlated with each other across all simulated and real radiographs (Spearman's rho=0.86-0.99, P<0.01). For both readers and hips, migration percentages measured from real radiographs were significantly different from those measured from neutral simulated radiographs (P<0.01), with median absolute difference=5-6 percentage points (PP) and interquartile range (IQR)=9-12 PP. When comparing migration percentage measurements from neutral simulated radiographs to those in kyphosis/lordosis and right/left rotations, median absolute differences were 2-4 PP (IQR=3-8 PP) and 4-15 PP (IQR=6-17 PP), respectively. Inter-rater reliability of measured migration percentages is high, but accuracy decreases with patient positional changes.

Acetabular index as an indicator of Pavlik harness success in grade I developmental dysplasia of the hip: A retrospective study.

Some articles have focused on the effectiveness of the Pavlik harness treatment for unstable and dislocated hips, yet data on monitoring its effectiveness with the acetabular index remains elusive. Therefore, this study aimed to assess Pavlik harness effectiveness in infants ≤6 months diagnosed with grade I developmental dysplasia of the hip using acetabular index improvement and identify the possible predictors of successful Pavlik harness treatment. A retrospective review of infants with grade I acetabular dysplasia treated with a Pavlik harness and monitored with anteroposterior pelvis X-rays at presentation and follow-up. Successful treatment was defined as achieving an acetabular index <30°. A total of 231 infants with acetabular dysplasia were treated with a Pavlik harness. A successful outcome was achieved in 135 infants (58.4%). Younger age, lower initial acetabular index, and patients with unilateral developmental dysplasia of the hip were significant predictors of a successful outcome. An age of 4.5 months or older was found to be the threshold for an unsuccessful result following Pavlik harness treatment, with a sensitivity of 65.2% and specificity of 57.3%. An initial acetabular index of 35.5° was found to be the threshold for an unsuccessful result, with a sensitivity of 83.7% and specificity of 61.5%. Pavlik Harness's success in correcting the acetabular index in acetabular dysplasia patients was related to unilateral cases, a younger age at presentation, and a lower initial acetabular index. The thresholds for unsuccessful treatment were an age of 4.5 months or greater and an acetabular index of 35.5° or higher.

Can we determine anterior hip coverage from pelvic anteroposterior radiographs? A study of patients with hip dysplasia

PurposeInsufficient coverage causes hip joint instability and results in hip pain. Anterior hip coverage can be determined on both pelvic anteroposterior (AP) radiographs and false profile (FP) radiographs. Four parameters are commonly used to determine the anterior coverage on pelvic AP radiographs: the crossover index, crossover sign, anterior wall index (AWI), and rule of thirds. This study aims to clarify the relationship between these 4 parameters on AP radiographs and the anterior center edge angle (ACEA) on FP radiographs.MethodsIn this study, 53 patients who underwent periacetabular osteotomy for hip dysplasia at our center between July 2020 and October 2020 were retrospectively reviewed. Four parameters on AP radiographs and the ACEA on FP radiographs before surgery and 6 months after surgery were measured and compared for each hip.ResultsUpon examining the 53 hips in this study, there was no correlation between either the crossover index and the ACEA (P = 0.66) or the crossover sign before surgery. The postoperative correlation between the crossover index and the ACEA was weak (r = 0.36, P = 0.007), and that between the crossover sign and the ACEA was moderate (r = 0.41, P = 0.003). There was a weak correlation between the AWI and ACEA both before (r = 0.288, P = 0.036) and after (r = 0.349, P = 0.011) the operation. Evaluation of the anterior coverage by the rule of thirds was also not consistent when determining the anterior coverage with the ACEA.ConclusionAnterior coverage on AP radiographs is largely inconsistent with ACEA on FP radiographs, especially before the surgery. It is recommended to take FP radiographs routinely for determining anterior hip coverage.

The role of Grey Scale Inversion Imaging (GSII) as a diagnostic tool of neck of femur fractures: is it more effective?

Grey Scale Inversion Imaging (GSII), a radiology reading software, has been utilized to improve anatomical and pathological delineation and consequently increase the diagnostic accuracy in a variety of trauma and Orthopaedic conditions. The objective of this study was to assess whether Grey Scale Inversion Imaging (GSII) has any impact on the diagnostic accuracy and inter-observer reliability in diagnosing neck of femur fractures. We performed a retrospective, single-centre study, to identify 50 consecutive anteroposterior (AP) pelvis radiographs of patients who presented to our unit with suspected neck of femur fractures between 2020 and 2021. The images included a combination of normal pelvic radiographs and others with features suggestive either intracapsular or extracapsular neck of femur fractures, which had been confirmed on computed tomography (CT), magnetic resonance imaging (MRI) and/or subsequent surgery. Four independent observers (two Trauma and Orthopaedics (T&O) consultants, one T&O Trainee Registrar (ST3 level) and one Trainee Senior House Officer (SHO in T&O) reviewed the images and graded each radiograph image using the Likert scale in response to the statement "there is a fracture". Following this, the same radiographs were inverted to Grey Scale Inversion Imaging (GSII) grey scale images and reassessed. RAND correlation was used for statistical analysis. Overall, observers appeared to have similar accuracy with normal radiographic imaging and with GSI sequences. Grey Scale Inversion Imaging (GSII) of digital radiographs did not affect the diagnostic accuracy of detecting neck of femur fractures in our study.